乙醇对鲍鱼碱性磷酸酶活力与构象的影响

以乙醇为效应物研究对鲍鱼碱性磷酸酶(ALP)活力影响的结果表明．酶的剩余活力随着乙醇浓度增大而迅速下降，乙醇浓度40％可使酶活力完全丧失．说明乙醇对鲍鱼ALP有明显的失活作用，JG50为13％．含较低浓度乙醇(30％)的失活过程是可逆的反应．测定乙醇对酶的失活作用机理．结果表明乙醇对鲍鱼ALP的失活作用是非竞争性机制，说明底物存在不影响乙醇对酶的失活作用．应用荧光光谱、紫外吸收光谱研究鲍鱼ALP经乙醇微扰后的分子构象变化，发现乙醇对酶分子构象有显的影响，酶的内源荧光强度随乙醇浓度增大而增强．荧光发射峰逐渐发生红移．紫外吸收光谱在276nm吸收峰随乙醇浓度增大而增强．这些结果表明．酶蛋白分子中的生色基团残基的微环境发生变化．

Effect of Ethanol on Activity and Conformation of Alkaline Phosphatase from Haliotis diversicolor

The effect of ethanol on the activity of H.diversicolor alkaline phosphatase has been studied. The results showed that the enzyme activity rapidly declined with increasing ethanol concentrations.The inactivation of the enzyme in ethanol solutions was reversible reaction.The inactivation of ethanol on the enzyme was found to be noncompetitive type and the presence of substrate did not influence the inactivation of the enzyme.The conformational changes of the enzyme in different concentrations of ethanol solution were measured by fluorescence absorption spectra and ultraviolet absorption spectra.The fluorescence emission peak in intensity of the enzyme gradually strengthened with increasing ethanol concentrations,accompanied by the peak being gradually red-shifted.The ultraviolet absorption spectra peak at 278 nm of the enzyme denatured in ethanol solution increased with increasing ethanol concentrations.Those results were in concordance with the conformational changes of the microenvironments of tyrosine and tryptophan residues of the enzyme.We can recognized that conformational integrity is important for maintaining the activity of the enzyme and slight changes at the activity site could lead to complete inactivation of the enzyme.The study of relationship between conformation and activity of the enzyme may give us some information and would be of great benefit to the H.diversicolor's culture.